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Abstract

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

This study tested the hypothesis that hepatitis C virus (HCV) RNA and core antigen levels rise more rapidly after liver transplantation (LT) in recipients of grafts from living donors (LD) versus deceased donors (DD). Eleven consecutive LD and 15 DD recipients were followed prospectively. Before LT, median HCV RNA levels were similar: 5.42 (LDLT) and 5.07 (DDLT) log10 IU/mL (P = NS). During the first 7 hours after LT a trend toward a greater HCV RNA decrease in LDLT patients was seen, although they received fewer blood replacement products during surgery. HCV RNA levels rose more rapidly in LDLT patients between days 1 and 3 (P = .0059) and were higher in this group on days 2, 3, 4, and 5. Core antigen levels were significantly higher in LDLT patients on days 3 and 5, although they were similar before LT (P = NS). Alanine aminotransferase (ALT) values were higher among LDLT patients from 8 to 14 days and from 4 to 24 months. Two-year graft and patient survival were 73% for LDLT patients and 80% for DDLT patients (P = NS). In conclusion, viral load rose more rapidly in LD recipients and reached higher levels shortly after surgery. Greater ALT elevations were evident in the LDLT group, but survival rates were similar. The trend toward a greater initial viral load decrease in patients with LD grafts and the significantly sharper increase suggest that the liver plays a predominant role in both HCV clearance and replication. (HEPATOLOGY 2005;42:1420–1428.)

After transplantation of hepatitis C virus (HCV) patients, viral infection of the graft is nearly universal, providing a unique opportunity to examine interactions between the human liver and HCV. Grafts from living donors (LDs) differ from grafts from deceased donors (DDs) in characteristics such as the rapid increase in volume that occurs in LD grafts during the first week after surgery.1 Several studies have compared outcomes of LD liver transplantation (LDLT) and DDLT in HCV patients.2–11 Results have been inconsistent, in part, because of differences in experimental design and small sample sizes.12–17 Concerning survival, no short-term difference was observed in a study of 65 DD versus 35 LD patients,6 and analysis of the United Network for Organ Sharing liver transplant database showed that the 2-year survival of 279 LD and 3,955 DD recipients was virtually identical.5 Other analyses of the same database, however, showed that graft survival was lower in LD recipients.4, 8 Studies of biopsy specimens have yielded conflicting results regarding the severity of recurrent hepatitis and the rate of progressive graft injury.7, 10, 11

HCV may interact differently with LD grafts than with DD grafts, and this difference may lead to greater LD graft injury. Exceptionally high HCV RNA levels in the early postoperative period are associated with greater long-term liver damage in DDLT patients,18, 19 and a similar association may exist in LDLT patients. The population of dividing cells in LD grafts is expected to be higher than in DD grafts. If HCV replicates more efficiently in dividing cells, as suggested by studies of replicons20 and the HCV translational apparatus,21 LD grafts may experience a burst of HCV replication during the first week after LT, when graft volume is increasing most rapidly.1 Garcia-Retortillo et al.10 found a positive relationship between the increase in liver volume in HCV LDLT patients and adverse outcomes.

Because little information is available regarding early viral kinetics in LD graft recipients or on the impact of early kinetics on clinical outcome, we compared changes in viral load and 2-year survival rates in LDLT and DDLT patients. To increase the robustness of the study, we used 2 independent assays to determine viral load: one for HCV RNA and the other for the HCV nucleocapsid (core) protein.22 Portions of the data were presented in oral form at the 2002 and 2004 AASLD meetings.23, 24

Patients and Methods

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

Study Populations.

Eleven consecutive viremic LDLT patients and 15 consecutive DDLT patients undergoing LT for HCV cirrhosis were enrolled between May and November 2001 at The Mount Sinai Medical Center and followed prospectively for 2 years. Blood was collected before and at multiple times after surgery. Sera were separated and stored at −70°C. One DDLT patient was lost to clinical follow-up at 6 months but remains alive and in communication. All procedures were performed with informed consent under protocols approved by the IRB of The Mount Sinai Medical Center. Before this study began, 78 adult-to-adult LDLT operations had been performed at this institution.

Medications.

Immunosuppression was managed similarly for DDLT and LDLT patients. Patients received intravenous intraoperative methylprednisolone (500 mg) followed by a taper dose on postoperative days 1 through 4. On day 5, patients were started on 20 mg daily prednisone. The goal was to withdraw corticosteroids within 8 to 12 months; doses were decreased by approximately 2.5 mg each month. All patients received an interleukin-2 receptor antagonist, basiliximab or daclizumab, in the immediate postoperative period and were started on tacrolimus 3 to 5 days after transplantation. In the setting of renal dysfunction, the dose of tacrolimus was decreased, and mycophenolate mofetil was added. No patient discontinued tacrolimus during the first 3 months, the period when viral load was measured; however, some patients later switched to cyclosporin. Dosing was adjusted with the goal of maintaining tacrolimus levels between 5 and 10 ng/mL, and cyclosporine levels between 150 and 300 ng/mL. Acute rejection, staged by the Banff criteria,25 was treated with 1 g methylprednisolone if it was moderate in severity, and with 2 g over 2 days, if severe. Mild acute rejection was not treated except for 1 DDLT patient, whose mild rejection 6 months after LT was treated with 1 g methylprednisolone.

Patients were offered interferon/ribavirin treatment when there was histological evidence of recurrent disease and the patient was believed to be a suitable candidate for treatment; that is, they did not have serious depression or hematological dysfunction. Some patients refused treatment. Combination therapy was initiated at 1.5 MIU interferon (IFN) alpha 2b 3 times per week and 400 to 800 mg ribavirin daily. Doses were increased as tolerated by the patient in an attempt to reach 3 MIU IFN 3 times per week and a ribavirin dose of 1,000 to 1,200 mg/day based on the patient's weight. No patient received IFN treatment during the 2-week period when viral load was measured.

HCV RNA and Core Antigen Quantitation.

The Roche Cobas Amplicor Monitor 2.0 Assay (Nutley, NJ) was used to determine HCV RNA levels. The lower limit of detection was 600 IU/mL. Samples with titers ranging from 600 to 600,000 IU/mL were tested directly; samples with higher titers were diluted as needed to obtain a value in the linear range of the assay. Approximately 4% of the samples with values over 600,000 could not be retested at greater dilutions because the sample was consumed in the initial testing. The Ortho-Clinical Diagnostics Trak-C Assay (Raritan, NJ) was used to determine core antigen levels before LT and on post-surgical days 3, 5, 7, and 14. Core antigen levels were determined with reference to a standard curve, according to the supplier's specifications, and are expressed in arbitrary units, rather than pg/mL, because the core antigen assay includes steps in which the reaction conditions used to generate standard curves and the conditions used to test sera differ significantly. For example, serum samples are treated with detergent (to release core protein from complexes), but the core-fusion protein used to generate the standard curve is not. This disparity opens up the possibility that the specific activity of core protein in serum and the core antigen in the standard curve reactions will differ. The arbitrary units presented here convert directly to the pg/mL units reported elsewhere.

Histopathology.

Liver biopsies were performed as clinically indicated by abnormal liver chemistry tests and not according to a protocol. The 1997 Banff schema were used to grade acute rejection25 semiquantitatively: indeterminate, mild, moderate, severe. A diagnosis of recurrent hepatitis C was made when portal and lobular inflammation consisted of lymphocytes, and the necroinflammatory changes were spotty throughout the lobules. If morphological evidence of chronicity was seen, the Scheuer grading and staging system for chronic hepatitis was applied.26

Data Analysis and Statistical Methods.

Samples were collected before surgery and after graft revascularization at a median of 7.15 hours and 14.87 hours in LDLT patients and at 6.23 hours and 19.03 hours in DDLT patients. Subsequent samples were collected at 24-hour intervals. Values of HCV RNA at specified times [7 hours, 17 hours, and 17+ (24)n hours] were determined by interpolation in Excel. Comparisons of patient characteristics and of (log10 transformed) RNA and core antigen were by t tests or Wilcoxon tests, as appropriate, for continuous data; and by exact chi-square or Fisher's exact tests for binary and ordinal data. Serial values of alanine aminotransferase (ALT) over specified periods were analyzed by methods for repeated measures within the framework of hierarchial mixed models. The comparison of the survival curves was made by the log-rank test. A P value of less than .05 was considered to be significant. Data analyses were performed using Excel and SAS software (Cary, NC) on a PC.

Results

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

Pretransplantation Characteristics

The median age of LDLT patients was 54 years, versus 53 years in the DDLT patients (Table 1). The median age of living donors was 33 years, versus 47 years among deceased donors (P = .17). No LDLT patient was United Network for Organ Sharing status 2A, whereas all DDLT patients were in this category, indicating that the LDLT patients were in a better state of health (P < .0001). Although the MELD system was not used at the time, MELD scores were calculated from medical records. They showed a trend toward lower values in LDLT patients (P = .05). Serum HCV RNA (log10 transformed) were similar in the 11 LDLT (median, 5.42) and 15 DDLT (median, 5.07) patients before liver transplantation (Table 1; P = .50). Median core antigen levels were 16 U/mL in the LDLT patients and 16.8 U/mL in the DDLT patients (P = .70).

Table 1. Baseline Characteristics (Median Values and Range) of the Two Patient Groups
VariableLDLTDDLTP*
  • Abbreviations: LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation; HCC, hepatocellular carcinoma; UNOS, United Network for Organ Sharing; HCV, hepatitis C virus.

  • *

    The Mann-Whitney test was used for patient age and MELD; t test for donor age; Fisher's exact for HCC; exact chi square test for trends for UNOS; Wilcoxon for log10 HCV RNA and core antigen.

  • Log transformed HCV RNA concentration (IU/mL).

  • Core antigen levels in arbitrary units/mL determined by reference to a standard curve.

N1115
Age of the patient (yrs)54 (50-66)53 (44-65).23
Age of donor (yrs)33 (20-54)47 (13-73).17
HCC41.13
UNOS 2A015<.0001
  2B50
  360
Calculated MELD14 (9-19)18 (10-31).05
HCV RNA5.42 (4.61-6.21)5.07 (3.57-6.17).50
HCV core antigen16 (0-60.4)16.8 (0-71).70

Transplantation.

LDLT patients had much lower blood transfusion requirements during LT, as expected based on their lower United Network for Organ Sharing status (Table 2). The median duration of total graft ischemia was much lower in the LDLT patients (80 minutes compared with 600 minutes; P < .0001). Almost all of this difference was accounted for by the DD grafts' longer periods of cold ischemia. Operative times were longer for LDLT patients (9.5 vs. 6 hours; P = .0003). The LD grafts were significantly smaller than the DD grafts (960 g vs. 1,415 g, P = .0002), and the graft-to-recipient body weight ratios of the LDLT patients were significantly smaller (1.27% vs. 1.72%, P = .003).

Table 2. Use of Blood Products and Additional Preoperative and Intraoperative Data
VariableLDLTDDLTP*
  • NOTE. Values are expressed as median (range).

  • Abbreviations: LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation; G/BWR, graft/body weight ratio.

  • *

    t tests were used for analysis of packed red blood cells, fresh frozen plasma, total and warm ischemia, surgery time, graft mass, and G/BWR; Mann-Whitney was used for platelets and cold ischemia.

Packed red blood cells (units)6 (1-8)9.5 (2-27).011
Fresh frozen plasma (units)6 (1-10)9 (4-23).027
Platelets (units)0 (0-5)5 (0-10).0084
Total Ischemia (min)80 (45-95)600 (46-972)<.0001
Warm Ischemia (min)34 (13-61)41 (24-55).47
Cold Ischemia (min)35 (20-64)608 (266-1,219)<.0001
Surgery (hr)9.5 (8-14.5)6 (4-11).0003
Graft mass (g)960 (670-1180)1415 (925-2,290).0002
G/BWR (%)1.27 (0.68-1.6)1.72 (0.9-2.6).0027

Early Viral Kinetics

HCV RNA Levels Decreased More Rapidly in LDLT Patients.

A comparison of HCV RNA before LT and at 7 hours after graft revascularization showed a nonsignificant trend toward a greater log decrease in HCV RNA in LDLT patients than in DDLT patients (Figs. 1 and 2). The median decrease was 2.04 log10 IU/mL in LDLT patients and 1.67 log10 IU/mL in DDLT patients (P = .16). This trend is noteworthy because the LDLT patients received smaller amounts of blood replacement products during surgery than the DDLT patients and thus lost less of their HCV viral load through bleeding. The LDLT patient with the smallest decrease, 0.55 log10 IU/mL, received a small-for-size graft (arrow in Fig. 1 and circle in Fig. 2). The graft/body weight ratio was only 0.68%, less than the recommended minimum of 0.8%.27–29

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Figure 1. Changes in HCV RNA levels during the first 14 days after transplantation: (A) LDLT; (B) DDLT. After log10 transformation, the pre-LT values of HCV RNA were compared with those after surgery. Samples were obtained at approximately 7 and 17 hours after revascularization of the graft and at daily intervals thereafter, as described in Patients and Methods. Data from the 4 LDLT and the 2 DDLT patients whose donors were younger than 30 years of age are in white; those of other patients are in black. An arrow marks the 7-hour timepoint of an LDLT patient with a graft-to-recipient body weight ratio of 0.68%. HCV, hepatitis C virus; LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation.

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Figure 2. Changes in HCV RNA levels during the first 7 hours after revascularization of the graft: (A) LDLT; (B) DDLT. Each patient's pre-LT log 10 HCV RNA IU/mL value was compared with the 7-hour point. In the LDLT group, the median decrease was 2.04 log10 IU/mL; the range was 0.55 to 2.77; and the 25% to 75% portion was 1.72 to 2.40. In the DDLT group, the median of the decrease was 1.66 log10 IU/mL; the range was 0.20 to 3.15; and the 25% to 75% portion was 0.83 to 2.01. A circle indicates the value of an LDLT patient with a graft-to-recipient body weight ratio of 0.68%. The horizontal line at the 2.77 log10 IU/mL marks the low-end cutoff of the assay (600 IU/mL). HCV, hepatitis C virus; LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation.

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Viral Load Increased More Rapidly in LDLT Patients and Was Higher During the First Two Weeks After Surgery.

After the initial decline, HCV RNA levels were higher in the LDLT group at all post-LT time points (Table 3). Serum levels of HCV RNA rose more quickly in LDLT patients than in DDLT patients during the intervals between 17 hours (day 1) and 65 hours (day 3) (Fig. 3, compare panels A and B). The median increase was 1.01 log10 IU/mL in LDLT patients and 0.37 in DDLT patients (P = .0059). Interestingly, HCV RNA levels did not rise as rapidly in the 4 LDLT patients and the 2 DDLT who received grafts from donors who were younger than 30 years as they did in the remainder of the patients (see Figs. 1 and 3, data in white), suggesting that grafts from younger donors may be partially resistant to HCV. Because there was a nonsignificant trend toward younger donors in the LD group (Table 1), and yet HCV RNA levels rose more rapidly in the LDLT group, any protective effect of younger average donor age was, evidently, insufficient to protect the LDLT patients as a group from a burst of HCV replication during the first week after LT. HCV RNA levels were significantly higher in LDLT patients than in DDLT patients on post-LT day 2 (median 4.96 vs. 3.81; P = .033), day 3 (5.33 vs. 4.12; P = .017), day 4 (5.47 vs. 4.14; P = .033), and day 5 (5.65 vs. 4.57; P = .038). HCV RNA values in LDLT patients were nonsignificantly higher on post-LT days 6, 7, and 14 (Table 3).

Table 3. Log10 IU/mL HCV RNA: LDLT Versus DDLT
TimeLDLT HCV RNA*DDLT HCV RNAP
MedianRange25%-75%MedianRange25%-75%
  • Abbreviations: LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation; HCC, hepatocellular carcinoma.

  • *

    Samples with HCV RNA levels below the low-end cut off of the assay, 600 IU/mL (2.77 log10) were assumed to have a value midway between 0 and 600, i.e., 2.48 log10 IU/mL, unless the testing laboratory generated a specific value, in which case that number was used. Samples were collected before surgery and after graft revascularization, at a median of 7.15 hours and 14.87 hours in LDLT patients and 6.23 hours and 19.03 hours in DDLT patients. Subsequent samples were collected at 24-hour intervals. Values of HCV RNA at specified time points, e.g., 7 hours, 17 hours, and 17+(24)n hours, were determined by interpolation.

  • Analyzed by the Wilcoxon Rank Sums test, comparisons with P < .05 are in bold.

Pre-OLT5.424.61-6.214.83-5.725.073.57-6.174.49-5.55.50
Day 0 7 hr3.242.43-5.172.61-3.813.522.47-5.372.48-3.91.64
Day 1 17 hr3.302.19-4.912.76-4.423.152.42-5.562.48-3.87.53
Day 2 41 hr4.962.48-5.383.62-5.183.812.37-5.742.48-4.51.033
Day 3 65 hr5.332.59-5.854.26-5.604.122.19-5.672.48-4.69.017
Day 4 89 hr5.472.47-6.694.91-5.694.142.47-6.082.53-4.90.033
Day 5 113 hr5.652.41-6.735.09-6.264.572.18-6.382.81-5.20.038
Day 6 137 hr5.542.49-6.754.79-6.054.982.32-6.462.70-5.38.097
Day 7 161 hr5.772.65-6.615.29-6.105.362.42-6.393.75-5.74.097
Day 14 329 hr5.734.28-7.324.74-6.405.372.14-6.963.29-6.38.39
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Figure 3. Increases in HCV RNA levels between 17 hours (day 1) and 65 hours (day 3) after LT: (A) LDLT and (B) DDLT. Serum levels of HCV RNA at 17 hours after LT (day 1) were compared with those at 65 hours after LT (day 3). The log10 IU/mL values of HCV RNA at the 2 times are plotted for each patient. In the LDLT group, the median increase was 1.01 log10 IU/mL; the range was 0.11 to 2.57; and the 25% to 75% portion was 0.52 to 2.07. In the DDLT group, the median increase was 0.37 log10 IU/mL; the range was −0.28 to 1.54; and the 25% to 75% portion was 0.00 to 0.70. Data in white represent patients whose donors were younger than 30 years of age. The horizontal line at 2.77 log10 IU/mL marks the low-end cutoff of the assay (600 IU/mL). HCV, hepatitis C virus; LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation.

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Core (Nucleocapsid) Antigen Assays.

To examine viral load using a second assay, core antigen levels were measured before surgery and on post-LT days 3, 5, 7, and 14. The core antigen is HCV's nucleocapsid protein. Core antigen levels were nonsignificantly lower in LDLT patients before LT, but they were significantly higher in the LDLT patients on days 3 and 5, and remained nonsignificantly higher on days 7 and 14 (Table 4).

Table 4. Core Antigen: LDLT Versus DDLT
TimeLDLT Core Antigen*DDLT Core AntigenP
  • Abbreviations: LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation.

  • *

    Core antigen levels are expressed in arbitrary units/mL (see Patients and Methods).

  • Analyzed by the Wilcoxon rank sum test.

Pre-LT16 (0-60.4)16.8 (0-71).70
Day 323.2 (0-735)0 (0-145).0046
Day 553.5 (0-1105)0 (0-545).0089
Day 7108.4 (0-785)37.2 (0-1,529).14
Day 1469.5 (0-2276)22.3 (0-1,100).25

The availability of both HCV RNA and core antigen data permitted the ratio of HCV RNA to core antigen to be analyzed in a subset of 9 LDLT and 6 DDLT patients whose antigen and RNA values exceeded the low end cutoff of the assays before LT and on postsurgical days 3, 5, 7, and 14. Previous studies show that the ratio of HCV RNA to core antigen is not fixed. A range of 50 to 20,000 IU HCV RNA/pg HCV core antigen was reported recently.22 Some evidence suggests that the ratio of HCV RNA to core antigen has prognostic value.22, 30 For the comparison of pre-LT samples to all post-LT samples, there was a nonsignificant trend toward a decrease in the ratio of HCV RNA to core antigen (14,000 vs. 8,000; P = .34). The difference in the ratio was statistically significant for the comparison of pre-LT samples with day 7 samples (14,000 vs. 3,500; P = .03).

Persistent ALT Elevations in LDLT Patients

ALT was measured daily during the first 2 weeks after LT, with occasional missing values. Repeated measures analysis revealed a nonsignificant trend toward lower average values in LDLT patients from post-LT day 1 to day 4 (P = .12, Fig. 4A-I). During this period, the values for the LDLT and the DDLT patients were changing in a similar way, showing a general downward trend (P < .0001). The findings on days 5 through 7 were similar to those on days 1 through 4 (P = .18 for the difference between groups, P = .005 for overall time effect, Fig. 4A-II), except that on days 5 through 7 the pattern of change differed significantly between the groups (P = .006), with DDLT values decreasing while LDLT were holding steady.

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Figure 4. LDLT patients have higher ALT values than DDLT patients during most time periods after LT: (A) Pre-LT and daily intervals after LT; (B) Monthly intervals after LT. Black (LDLT), gray (DDLT). ALT, alanine aminotransferase; HCV, hepatitis C virus; LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation.

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By the second week after LT (days 8 to 14), average ALT values of the LDLT patients were significantly higher than those of the DDLT patients (P = .01, Fig. 4A-III). The rate of decrease during the second week after transplantation was similar for both groups (P < .0001). From day 8 to 2 years, values were obtained more sporadically than during the early post-LT period. During the time from day 14 to 3 months, the average values of the LDLT patients remained higher than those of DDLT patients, but the difference was not statistically significant (P = .18, Fig. 4B-IV). The values continued to decrease at a similar rate for the 2 groups (P = .006 for the average slope; nonsignificant interaction term). The values for both groups held steady during the period from the fourth month to 2 years after LT (P = .84 for the average slope; nonsignificant interaction term Fig. 4B-V), with the average values of the LDLT patients significantly higher than those of the DDLT patients (P = .01).

Interferon/Ribavirin Therapy

Patients diagnosed with recurrent disease were offered treatment with interferon and ribavirin. LDLT patients received treatment on a total of 2,452 of 6,599 post-LT days, whereas DDLT patients received treatment on a total of 2,161 of 10,010 days. IFN was not used during the first 14 days.

Survival and Histopathology

Two-year graft and patient survival were similar (Fig. 5) : 8 (73%) of 11 for the LDLT patients and 12 (80%) of 15 for DDLT patients (P = NS). Biopsies were performed when clinically indicated and not according to a protocol. No statistically significant histological differences were found. Five of 11 LDLT patients and 5 of 15 DDLT patients were diagnosed with rejection (P = NS); 2 of 11 LDLT and 3 of 15 DDLT were treated with methylprednisolone or OKT3 (P = NS).

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Figure 5. Graft and patient survival. Solid line: LDLT; dotted line: DDLT. LDLT, living donor liver transplantation; DDLT, deceased donor liver transplantation.

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Discussion

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

HCV RNA and Core Antigen Levels.

This study confirmed the hypothesis that LDLT patients have faster viral kinetics. Levels of both HCV RNA and core antigen were higher in LDLT patients than in DDLT patients during the first week after surgery. The differences in HCV RNA levels were statistically significant on post-LT days 2 through 5, and the differences in core antigen levels were statistically significant on days 3 and 5. Median HCV RNA levels on post-LT days 2 through 5 were more than a log higher in the LDLT group. The assays used to measure HCV RNA and HCV core antigen technically are very different from each other. The concordance of the HCV RNA and the core antigen data reinforce the conclusion that viral load is higher in LDLT patients than in DDLT patients during the early postoperative period.

In theory, at least 4 mechanisms might contribute to these higher levels: (1) Cellular proliferation is enhanced, creating a cell population in which the HCV replication rate is higher, as previously discussed11, 23, 24; (2) The HCV-susceptible cells in LD grafts are in a superior functional state, and this leads to enhanced HCV replication; (3) The LD grafts receive a larger inoculum of virus because of more efficient uptake, coupled with less loss during surgery, and thus they have more foci of viral production; and (4) The smaller size of LD grafts compromises their ability to metabolize drugs, resulting in excessive immunosuppression and reduced antiviral defenses. In all likelihood, several mechanisms, including some not listed above, act in concert.

Of the various factors that may influence viral kinetics, the state of antiviral defenses merits special attention because it can potentially be modulated to beneficial clinical effect. Garcia-Retortillo et al.31 found that 5 of 7 patients who were not treated with corticosteriods had a second-phase decline in viral load, whereas this pattern was observed in only 1 of 13 patients who received corticosteroids, suggesting that immunosuppressive regimens that lack corticosteroids may slow viral propagation. The concept that anti-viral defenses can suppress HCV during the early postoperative period finds some support in our preliminary observation that HCV RNA levels remained relatively low (<100,000 IU/mL) during the first 14 days after LT in 2 of 4 LDLT and 2 of 2 DDLT patients whose donors were younger than age 30. This suggests that the age of the donor may have an impact on early viral kinetics—with younger donor age militating against HCV multiplication. Younger grafts may metabolize drugs more efficiently, have stronger innate anti-viral defenses, and turn over HCV more efficiently. We used a uniform immunosuppressive regimen, which minimized variability in our study; however, steroid doses were not adjusted for graft size and function. Trotter et al.32 previously reported that LDLT patients achieve higher blood levels of tacrolimus and cyclosporine A for a given dose. If the same is true of steroids, our LDLT patients may have received a higher effective dose than the DDLT patients. In the future, reducing the dose of steroids or switching to an alternative regimen in LDLT patients may be useful.

The primary objective of this study was to compare viral load during the first week after transplantation in LD and DD recipients. The observation that immediately after surgery viral load underwent a greater decline in the LDLT patients was an unanticipated but interesting finding that merits further investigation. The nonsignificant trend toward a greater decline in the LDLT patients is noteworthy because these patients had a much lower transfusion requirement during surgery than the DDLT patients and lost fewer HCV particles through bleeding. HCV RNA declined the least in a patient who received a small-for-size graft that showed evidence of substantial injury. The ALT value of this patient increased to 755 U/L during the first 24 hours after surgery, more than 3.5 times the median ALT value for the LDLT patients (208 U/L). Previous investigators also reported an association between prolonged viral elimination times and liver injury.31

We propose that better liver function is associated with more rapid viral clearance. The concept that HCV uptake correlates with liver function is supported by observations of Garcia-Retortillo et al.,31 who analyzed HCV kinetics in a patient whose graft was removed because of primary non-function and who was then anhepatic for 20 hours. During the anhepatic phase, the decline in viral load was minimal. It decreased by only 0.58 log10 IU/mL, and the deduced elimination half-life of HCV virions was 10.3 hours. After reperfusion of a second graft, serum levels of HCV rapidly declined, with a deduced elimination half-life of 3.75 hours, which was similar to that of the other patients (3.44 hours).

Our data do not indicate the relative amount of HCV that exits the blood to enter a compartment in which it replicates and the proportion that enters a compartment in which it is degraded. They do indicate that the mechanism(s) leading to viral removal operated consistently in the LDLT patients, yielding a similar rate of decline in these patients. With the exception of the patient noted above, the range in the LDLT group was 1.03 to 2.78 log10 IU/mL, whereas the range in the DDLT group was 0.20 to 3.15 log10 IU/mL. Thus, the rate of decrease was more heterogeneous in DDLT patients. As suggested by Dahari et al.,33 this variability may reflect an extrahepatic compartment that is larger in some patients than in others. Other factors that varied over a wider range in our DDLT patients than in our LDLT patients, such as donor age and the extent of ischemia–reperfusion injury, also may contribute to variability in the rate of viral load decrease in DDLT patients.

Clinical Outcomes.

ALT levels were significantly higher in LDLT patients than in DDLT patients by the 8th day after LT. This higher level persisted throughout the study period. Previous studies of DDLT patients indicate that ALT elevations are an unfavorable prognostic sign. Gretch and colleagues18 showed that persistent ALT elevations were associated with chronic active hepatitis in 1-year protocol biopsies. Pelletier and colleagues34 reported that patients with ALT elevations for 3 consecutive months had increased fibrosis. Despite the ALT elevations, the 2-year patient and graft survival rates were similar in our 2 patient groups: 73% among the LDLT patients and 80% among the DDLT patients. No patient in either group underwent retransplantation. The survival curves need to be interpreted in light of the trend toward younger age of LDLT donors. This probably benefited the LDLT patients, because advanced donor age has been previously associated with a decrease in patient survival.35, 36 The small size of our study limits our ability to draw general conclusions; however, our data suggest that the balance between the advantages (e.g., younger donor age) and disadvantages (e.g., more complex surgery) of LDLT versus DDLT strongly depend on the specific characteristics of the patient population, which vary from center to center.

When considering the long-term outcome of LT, it may be useful to note that allografts of HCV patients are reported to have an extraordinary rate of hepatocyte turnover that can lead to complete replacement within 2 weeks.37 This pace may be difficult to sustain, particularly for grafts that come from older donors and grafts that need to regenerate—either because they are small-for-size or because they were damaged during the transplantation procedure.

Conclusions.

LDLT patients have higher HCV RNA and core antigen levels than DDLT patients in the early post-LT period. The more rapid increase in the viral load in the LDLT patients followed a more rapid decrease in these levels during the first 7 hours after graft revascularization. Viral kinetics indicate that the liver plays a central role in both HCV clearance and production. They also suggest that grafts from younger donors may suppress viral replication for reasons that might include more effective antiviral defenses and more rapid drug metabolism. During 2 years of follow-up, LDLT patients were more likely to have persistently elevated ALT levels than DDLT patients, but 2-year graft and patient survival were similar. Thus, any deleterious effects of the accelerated early viral kinetics in the LDLT group were either offset by other factors or could not be detected in a study of this size and duration.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

The authors thank Roche Diagnostics for the gift of HCV Monitor assay kits, and Ortho Diagnostics of Johnson and Johnson for the Trak-C core antigen kits.

References

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References